Snap switch mechanism



June 12, 1951 E. c. RANEY 2,556,216

SNAP SWITCH MECHANISM Filed Jan. 17, 1948 .l I 2 \F INVENTOR. M 58 7'540. BAA/6') Patented June 12, 1951 SNAP swrrcn MECHANISM Estel C. Raney,Delaware, Ohio, assignor to Ranco, Incorporated,,Columbus, Ohio, atcorporation of Ohio Application January 17, 1948, Serial No. 2,822

2 Claims. (Cl. 200-67) The present invention relates to a snap switchmechanism and more particularly to a double throw snap switch in whichthe movable contact is moved with a snap action in opposite directions.

An object of the invention is to provide a double throw snap actingswitch which will maintain a positive contact pressure until the instantthat the contact is moved with a snap action from either contact to theopposite contact.

Another object of the invention is to provide a snap acting switch whichrequires a minimum of pressure to actuate the mechanism and at the sametime provides positive contact pressure as the switch actuating memberis gradually moved from one switch actuating position to the other.

Other objects and advantages of the invention will be apparent from thefollowing description of a preferred form of the invention, referencebeing made to the accompanying drawings wherein:

Fig. lis a side view in elevation of a double throw snap acting switch,parts thereof being broken away for the sake of clarity;

Fig. 2 is a plan view of the switch shown in Fi 1;

Fig. 3 is a diagrammatic illustration of the switch parts when theswitch is in one position;

Fig. 4 is a View similar to Fig. 3 but showin certain parts of theswitch in another position;

Fig. 5 is a view similar to Fig. 3, but showing the switch members inthe opposite position; and

Fig, 6 is a view similar to Fig. 4 but showing the switch members in theopposite position.

The present switching mechanism may be operated by any suitableactuating means such as by a thermostat or manually operated means, butfor the purposes of illustrating the invention I have shown a manuallyoperated switching mechanism indicated generally at 10. The mechanism Icomprises a base member II which is preferably formed of a suitabledielectric material. A rigid bracket I2 is riveted to the base II andthis bracket includes a platform portion I3 which is spaced from andextends parallel to the upper surface of base H. The ends of a U shapedstrip M are attached to the platform l3 by screws l and the yoked end ofthe strip has attached thereto a pair of contact members Hi. The stripI4 is preferably formed of a flexible, resilient material which is alsoa good electric conductor, such as beryllium copper, for example.

Two fixed contact posts 11, only one of which appears in thedrawings, isriveted to the base H and carry contact surfaces l8 which are engaged bythe contacts I6,'respectively. Suitable means, not shown, may beprovided for connecting lead wires to the contact post l1. Two brackets20 and 2! are attached at one end to opposite sides of the base H andthe opposite ends of these brackets extend above the base II and eachcarry a contact 22 which are disposed in alignment with the uppersurfaces of the respective contacts R6. The brackets 20 and 2| areriveted to the base and they are also provided with threaded openings 24for receiving terminal screws, not shown. The positions of the contacts22 relative to the base ll may be adjusted by screws 25 which arethreaded into openings in the brackets 20 and 2| so that by turning therespective screws 25 the brackets will be moved toward or away from thebase II respectively. It will be seen that the free end of the strip l4may be shifted between the two sets of fixed contacts l8 and 22 formaking and breaking two circuits through the switch.

The strip M is adapted to be shifted from one set of contacts to theother with a snap action by a toggle mechanism which comprises a togglemember 26 and a compression spring 3i. One end of the toggle member 26is pivoted on one end of a fixed plate 21 by a V bearing structure. Theopposite end of the plate 21 is anchored to the platform l3 of bracketl2 and the plate 21 is reinforced by strips 28 disposed on oppositesides thereof. The plate 21 and strips 28 are preferably of resilientmaterial normally flexed upwardly and the position of the pivot end ofplate 21 is fixed by the head of a screw 30, which screw extends throughan opening through the plate and strips and which is threaded into thebase II. The head of the screw 30 engages the upper plate 28 and therebypositions the end of plate 21 to which the toggle member 26 is pivoted.By adjusting the screw 36 the position of the pivot point for the togglemember 26 can be accurately fixed, and this point is adjusted to liemidway between the center line positions of strip 14 when the strip isin the positions to engage contacts [6 with contacts 18 and 22,respectively, as seen in Figs. 4 and 5.

As may be seen clearly in Fig. 2, the toggle member 26 is disposed to bein alignment with the opening between the legs of the strip 14,

and the C-shaped compression spring 3| is interposed between the freeend of the toggle member 26 and the yoke of the strip l4. 'As is shownin the drawings, the connections at the ends of the opening are V andknife edged to minimize friction. It will be seen by comparing Figs. 3,4 and 5 that the toggle member 26 and spring 3| form a toggle jointmovable from one side to the other of a dead center position, whichposition is indicated by the line 32 in Fig. 4. When the toggle member26 is in the lowered position as seen in Fig. 3, the spring 3| will urgethe member [4 upwardly so that contacts I6 will engage contacts 22. Whenthe of the strip The instant that member 26 passes snap movement, as isillustratedin Fig.5. The

same type of snap movement will occur in the opposite direction with thetoggle member passing through its dead center while the spring applies adownward force on strip M, :as may be seen inFig. 6.

In order to obtain the rapidsnap movement M by the toggle comprising themember 26 and spring 3! it is essential that the toggle member be freeto move after it has passed its dead center position. To provide forthis free movement the switch is adapted to be actuated by 'a memberwhich is connected to the toggle member 26 by a lost motion connection.The actuating member 35 consists of a U-shaped spring member'having theends of its legs anchored to the platform 13 of bracket 12. The outerend of the bracket has a downturned tongue 38 provided with a slot 3'?there- 'in through which the member 25 extends. The slot 3"! is somewhatlonger than the depth of the toggle member 26 so that as the togglemember is moved through dead center 'it will be free to travel from oneend of the slot to the other, thereby permitting a snap movement of thefree end of the toggle member to the opposite side of the center line ofstrip [4 and thereby impart a snap movement to the strip Id. In thepresent embodiment the actuating member 35 is normally biased upwardlyto normally maintain the switch mechanism in the position shown in Fig.5. The'actuating member may be depressed by any suitable type ofactuating device, and in Fig. 1 there is indicated a'cover '38 having apush button 39 reciprocable therein and engageable with the actuatingmember 35.

The snap switch just described isparticularly suitable for double throwswitches because it provides positive contactpressure up to the instantof snap movement of the movable 'contact carrier in opposite directions.It will be understood that the mechanism is suitable 'for single throwswitches, in which case either .one of the contacts It .or.22 could beeliminated and suitable stop members substituted therefor.

The snap mechanism enables relatively light weight parts to be utilized,thereby reducing the power necessary to actuate the switching mechanismso that the mechanism could be operated by sensitive thermal responsiveelements to provide close response to temperature conditions.

Although Ihavedescribed but one form of the invention it is to-be-understood that otheriorms might be adopted, all falling within thescope of the claims .which follow.

I claim:

1. A double throw snap acting switch mechanism comprising an elongatedstrip anchored atone end and having a contact at the .opposite end, apair .of spaced .stops between which said opposite end of said strip isadapted to shift, a toggle member extending in the same 4 generaldirection as said strip, means pivotally supporting one end of saidtoggle member intermediate the ends of said strip, the other end of saidtoggle member being swingable from one .side to the other of the centerline of said strip,

said strip being adapted to move from one side to "the other of the axisof the toggle member pivot assaidopposite end shifts between said stops,.acornpression spring having one end connectedto:theswingablc end ofsaid toggle memher and the opposite end connected with said stripadjacentto said opposite end, and an actuating means for moving saidtoggle member about its pivot, said means having a lost motionconnection withsaid toggle memberwhereby said swingable end of thetoggle member has limited .free swinging movement from one sicleof thecenter line of said strip to the other, said spring adapted to reactbetween said toggle.member and strip to urge said opposite end .of saidstrip to one or the other of saidstops .and .said .swingable end of saidtoggle member'toitslimit of movement. opposite to the stop engaged bysaid .strip.

2. A double throw snap acting switch mechanism comprising van elongatedstrip anchored at one end and having .a contact at the oppositeend, apair of spaced stops between which saidopposite end of said strip isadapted to shift, a toggle .member extending in the same generaldirection as said strip, means pivotally supporting one endof saidtoggle member approximately midway between the ends of said r ,stri-pthe other endof said toggle ,member being swingable from one side to theother of the center line ofsaid strip,saidstripbeing adaptedtotmoveifrom one .side tothe other of the axis of the toggle .memberpivot as said opposite end shifts between said stops, a compressionspring having one end connected to the swingableend of said togglemember and the opposite .end connected with said strip adjacent to saidopposite ,end of said strip, and an actuatingmeans for movingsaid togglemember about its pivot, said means having v.a lost motion connectionwith said toggle member whereby said swingable end of the toggle member.has limited free swinging movement from one side of the center line ofsaid strip to the-other, said spring adapted to react between saidtoggle .member and strip to urge said opposite end of said strip to oneor the otherof said stops andsaid swingable end of said toggle member toits limit of movement opposite to thestop engaged by ,said strip.

ESTEL C. RANEY.

'RE'EERENCES CITED The'fol1owing references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,995,877 -Woodworth Mar. 26,,1935 2,135,864 Weber Nov. 8, 1938 2,170,748 Eaton Aug. .22, 19392,228,523 Johnson Jan. "14, 1941 2,428,1?2 Miller Sept. 30, 19472,429,074 'Rugh Oct. 514, 1947 FOREIGN PATENTS Number Country Date551,021 .Great Britain Feb. A, :1943

